736 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [18] 



Habitat — Lophopsetta maculata, August 10, 1S87, Limanda ferruginea, 

 September 6, 1887, Wood's Holl, Massachusetts. 



4. Dibothrium microcephalum, Budolphi. 



[Place ii, Figs. 5-18.] 



Tcenia tetraodontis molw, Viborg, Ind. Mus. Vet. Hafn., 241 ; Rudolpbi, Eutoz. 



Hist, in, 213. 

 Bothriocephalw rnicrocephalus, Rudolphi, Synops., 138 and 473 ; Drummond, 



Charlsworth's Mag. Nat. Hist., iv, 241; Dujardin, Hist. Nat. des Helm., 



619; Bellinghain, Ann. Nat. Hist., xiv, 253; Von Linstow, Compeud., 



der Helm., 274; Olssou, Lund's Univ. Arssk., m, 55, and iv, 11; Van 



Beneden, Mem. Acad., Belgiqne, xxxviii, 87. 

 Bothriocephalus sagittatus, Leuckart, Zool. Brucbst., 39, PI. i, 15. 

 Dibothrium microceplialum, Rudolphi, DiesingSyst. Helm., i, 592; Sitzungsb., 



d. kais. Akad., xiii, 578; Revis. d. Cepb, par., 241 ; Wagener, Nov. Act. 



Nat. Cur., xxiv, Suppl. 16, 69, PI, vn, 77; Van Beneden. Bull. Acad., 



Belgique xxu, II, 521. 



Head, sagittate in marginal, oblong in lateral, view, with a rounded 

 button-like apex. Bothria lateral oblong, neck none, anterior part of 

 body slender subcylindrical, median and postero-median part broader 

 and thicker, narrower towards posterior. Body cylindrical or sub- 

 quadrate in front and rather thick throughout. First segments some- 

 what funnel-form, subsequently becoming very short and broad, pos- 

 terior segments short and narrow, squarish or sometimes indistinct. 



Genital apertures marginal. Length in alcoholic specimens as much 

 as 660 mm , greatest breadth 7.5 mm . 



A lot of Dibothria containing thirteen individuals from the intestine 

 of a suiifish (Mola rotunda) was collected by the U. IS. Fish Commission 

 off Martha's Vineyard, Massachusetts, September 10, 1886, and seut to 

 me after my return from the laboratory at Wood's Holl, Massachusetts. 

 I have therefore not had the opportunity of studying these parasites 

 while they were living. All the data for this description were derived 

 from the study of alcoholic specimens. 



I have experienced much difficulty in reconciling differences between 

 my specimens and previous descriptions. While I have little doubt 

 but that the specimens in question are specifically identical with those 

 figured by Wagener and Leuckart, there remains yet much to be de- 

 sired in the way of a detailed description of the animal. 



Among the thirteen specimens, all of which were adult and approxi- 

 mately of the same size, there was one which differed from the others in 

 having an extremely small head and smaller and narrower anterior 

 segments. The head had but little more than half the linear dimen- 

 sions of the others, while the anterior segments were longer by nearly 

 a third, and less than half as wide. The bothria, moreover, extended 

 but a little way back over the first segment, while in the others they 

 over-lapped the first two segments. The general outline of the head 

 remains in other respects much the same for the two varieties. 



